If Hermione had died on the hunt for the horcruxes, would her parents remember her?

Question

In Harry Potter and the Deathly Hallows, Hermione reveals that she wiped her parents' memory of ever having a daughter.

In The Half-Blood Prince, just before the confrontation between the Death Eaters (Snape and Malfoy) and Dumbledore, Dumbledore casts a body-bind curse on Harry to prevent him from leaving the Astronomy tower during the confrontation, but breaks when Dumbledore is killed.

If the memory charm (obliviate) is similar to the body-bind curse, would Hermione's parents remember her if she had died on the search for the horcruxes? Or is the memory charm more similar to the permanent sticking charm, wherein it is absolutely unbreakable, even if the person who cast the charm dies?

Answer 1

There are plenty of examples of magic outliving its creator; death does not undo all the magic you have ever done. Consider things like:

Dumbledore's protections on Hogwarts, Sirius's father's and Moody's protective charms on number 12 Grimmauld Place, the magical properties of ancient magical artefacts and all the permanent sticking charms.

I think you have to have to view some magic as active and some as a permanent change of property. Your grip on somebody's body or mind might be something that might only last as long as your magical powers allow, while transfiguring indicates that fundamental change and would outlive you.

Accepting that gives you two ways to look at what Hermione did:

• An active, imperius-style mind control. She could instruct them to leave the country and use her not-insignificant willpower to suggest they are different people, all without tramping on their underlying minds. Her death would mean they they remembered but by that point their strategic value (eg targeting them to get to Hermione) would be gone. They'd still be safe.

• A fundamental change of their minds to remove (or otherwise block) certain memories. It wouldn't reverse on her death, leaving them ignorant to her existence and demise. That said, obliviate was demonstrably dangerous and could irreversibly corrupt minds (Jorkins).

Either keeps them safe. I disagree with the current high answer, I don't think Voldemort would have had any use for them other than as a pressure point for Hermione.

The only mentions of memory modifications in the books are linked to the obliviate charm, so you would assume the second would be more true (especially if you infer a lasting blissful ignorance for her parents) but the danger of performing such a fundamental change on their minds might suggest it wasn't.

Ooo, with help from the Harry Potter Wikia page on Memory Charms, we can see that it wasn't obliviate:

In Chapter 9 of Deathly Hallows, just prior to erasing Antonin Dolohov and Thorfinn Rowle's memories, Hermione says that she has never performed a Memory Charm before, despite having already altered her parents' memories.

There's a webchat with JK Rowling where she confirms this:

They are two different charms. She has not wiped her parents’ memories (as she later does to Dolohov and Rowle); she has bewitched them to make them believe that they are different people.

As far as I know, there are no uses of this charm in the books that we can use to determine its permanency though.

Answer 2

Probably not.

The way Hermione describes the charm, it sounds as if she expects it to stick if she dies:

“I’ve also modified my parents’ memories so that they’re convinced they’re really called Wendell and Monica Wilkins, and that their life ambition is to move to Australia, which they have now done. That’s to make it more difficult for Voldemort to track them down and interrogate them about me — or you, because unfortunately, I’ve told them quite a bit about you.

“Assuming I survive our hunt for the Horcruxes, I’ll find Mum and Dad and lift the enchantment. If I don’t — well, I think I’ve cast a good enough charm to keep them safe and happy. Wendell and Monica Wilkins don’t know that they’ve got a daughter, you see.”

— Deathly Hallows, chapter 6 (The Ghoul in Pyjamas)

Even Hermione sounds somewhat unsure, but this could be because she doesn’t want to contemplate the possibility that she’d die and her parents would never remember her again. It’s more comfortable to phrase it as a hypothetical.

ETA: Two additional considerations:

• Her parents may still be in danger after she's dead.

  If Hermione's dead and their memory restored, then they have all the information they know about Harry, their plans, and what the rest of the Order might be doing. For example, if they've overheard anything about horcruxes, and that gets coerced out of them, then Harry's plan goes up in smoke. So I think Hermione would design this memory modification to outlive her, as a necessary precaution.

• This seems to be a "one-off" spell, not a continuous one.

  The rules about which spells are permanent, and which die with the caster, are fuzzy and poorly-defined. Here's one rough rule: spells which require continuous magic/mana (such as Imperius, or the full body-bind) die with the caster, because the source of the effect is gone. One-off incantations (like Avada Kedavra, or Obliviate) persist, because there's no reason for them to "snap back". The way she describes it sounds like a one-off, so it wouldn't undo itself if she died.

Answer 3

I think if you read behind the scenes part first 2 of them you will see what it is.

"However, J. K. Rowling has said this was a different charm[3], which alters memories rather than removes them."

I think that if she dies nothing would change, it is like a bit of extracting memories like used in pensieve, instead of removing them she replaces/blocks them.

As I recall she later removes the charm and memories are back.

http://harrypotter.wikia.com/wiki/Memory_Charm